Vented Sink Tailpiece

ABSTRACT

A vented tailpiece that may be used in existing sink installations is connected to a sink drain and a drainline trap as part of the sink drain line. A vent in the tailpiece releases air upstream of the drainline trap as the air is displaced by liquid flowing through the drain line. A retainer connected to the vent catches liquid escaping through the vent. The retainer may be fitted with an extension if necessary. An overflow valve, which is preferably a float valve, may be attached to the retainer and configured to prevent liquid from spilling out of the retainer if a problem in the drain line causes liquid to back up into the retainer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of co-pending provisional application Nos. 61/204,637 and 61/204,638, both filed Jan. 9, 2009.

FIELD OF INVENTION

This invention relates to plumbing devices. This invention relates particularly to an apparatus for improving the draining of liquid from a sink.

BACKGROUND

A typical sink installation comprises a sink with a drain connected to a tailpiece, the tailpiece connected to a drainline trap, such as a p-trap or s-trap, and the drainline trap connected to a drain elbow that connects to a drain pipe that transports liquid out of the installation to the sewer or other outlet. The sink drain is covered by a catch, such as a stationary grid cover or a pop-up stopper, to prevent articles from entering and clogging the piping. Unfortunately, an airlock occasionally forms on the underside of the catch, causing the sink to drain slowly by hindering or preventing the displacement of air from the tailpiece and piping, which is needed for liquid to flow out.

It is common to vent the piping in the installation downstream of the drainline trap, in order to relieve pressure from gas entering the piping from the outlet. A downstream vent is difficult to add to an existing installation because the pipes downstream of the drainline trap are usually inside a wall and cannot be accessed. More importantly, the downstream vent does not prevent the airlock under the sink catch from forming because the drainline trap is always filled with liquid, so that the problematic air is retained between the sink drain and the drainline trap. In order to release the trapped air, a vent between the sink drain and drainline trap is needed. It would be further advantageous if the vent could be added to the drainline after the sink is installed.

A sink overflow is a channel within the sink that runs from an open port near the top of the sink to a place below the sink drain. The sink overflow is designed to divert water from the sink to the piping once the liquid in the sink reaches a certain level. The sink overflow also helps to relieve the airlock when the channel is empty of liquid. However, the overflow channel is infrequently used, so it is common for mold, mildew, or bacteria to build up in the channel. The buildup can cause a foul odor to emanate from the overflow port, and can also attract pests. Further, the overflow port is an unwanted aesthetic distraction in vanity sinks.

More and more sinks, including vessel sinks and undermount sinks, are being built without overflows due to their drawbacks. These sinks are typically installed and put into use before the slow-draining problem is recognized. In order to retain the aesthetic value of these sinks, an after-market modification that is not visible and releases the trapped air is needed.

Therefore, it is an object of this invention to provide a device to relieve trapped air in a sink installation. It is a further object that the device relieve trapped air between the sink drain and the drainline trap. A further object is that the device be easily installed in an existing sink installation. A further object is that the device be hidden from plain view.

SUMMARY OF THE INVENTION

A vented tailpiece is connected to a sink drain and a drainline trap as part of the sink drain line. A vent in the tailpiece releases air upstream of the drainline trap as the air is displaced by liquid flowing through the drain line. A retainer connected to the vent catches liquid escaping through the vent. The retainer may be fitted with an extension if necessary. An overflow valve, which is preferably a float valve, may be attached to the retainer and configured to prevent liquid from spilling out of the retainer if a problem in the drain line causes liquid to back up into the retainer. The vented tailpiece may conform to one or more of the common plumbing sizes so that it may replace unvented tailpieces in existing sink installations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of the preferred vented tailpiece.

FIG. 2 is a top view of the vented tailpiece of FIG. 1.

FIG. 3 is a cross-sectional view of the preferred vented tailpiece installed between the sink and the p-trap.

FIG. 4 is a perspective view of an alternative vented tailpiece.

FIG. 5 is a perspective view of another alternative vented tailpiece.

FIG. 6 is a cross-sectional view of the tailpiece of FIG. 5 installed between the sink and the p-trap.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, there is illustrated the preferred embodiment of the present invention, a vented tailpiece for installation in a sink drain line. The components of the vented tailpiece may be made in varying dimensions to accommodate placement in any new or existing sink installations, such as those in residential, commercial, industrial, or medical environments. The vented tailpiece comprises a pipe 10 that may be made of any suitable plumbing material, including plastic such as polyvinyl chloride (“PVC”) and acrylonitrile butadiene styrene (“ABS”), and metals such as brass, stainless steel, copper, and zinc alloys. If the vented tailpiece is to be used in a medical environment, the pipe 10 and other components may be made of or coated in an antimicrobial material that is easily sterilized. The pipe 10 has a top end 11 that attaches to a sink drain and a bottom end 12 that attaches to a drainline trap. The pipe 10 may be threaded at the top end 11, the bottom end 12, and is preferably threaded at both ends 11, 12, to attach to the sink drain and drainline trap, respectively. Alternatively, the pipe 10 may have a flange (not shown) at one or both ends 11, 12 to fit over the sink drain, drainline trap, or both. The pipe 10 is preferably fabricated in dimensions that are common to existing tailpieces, so that the vented tailpiece may replace tailpieces in existing sink installations. Most preferably, the pipe 10 is from six to eight inches long.

A vent 13 provides access to the interior of the pipe 10 and is positioned on the surface of the pipe 10 between the top end 11 and bottom end 12. The vent 13 is a hole that allows air in the drain line between the sink drain and the drainline trap to be released from the drain line as it is displaced by liquid draining from the sink. The vent 13 may be any shape but is preferably substantially circular. The vent 13 has a diameter that is sufficient to allow air to escape, and may be as small as a pinhole. The preferred vent 13 diameter is about 0.375 inches. A vent 13 of about 0.75 inches to 1 inch in diameter is shown in the figures for the purpose of clarity. Using the top end 11 as a reference, the vent 13 may be placed any distance from the top end 11 that allows proper air release. This distance may be chosen depending on the existing sink installation in which the vented tailpiece will be used. Specifically, the pipe 10 may need to be longer or shorter to accommodate the existing sink installation. For standard sink installations, the pipe 10 is typically 6-8 inches long. The preferred pipe 10 is about 8 inches long with the vent 13 placed at the midway point of the pipe 10. Further, the preferred pipe 10 may be modified to fit the sink installation by cutting off part of the pipe 10 from the bottom end 12, and if the pipe 10 is not long enough for an existing installation it may be fitted with an appropriately-sized standard plumbing pipe extension. The vent 13 functions the same regardless of its radial position on the surface of the pipe 10.

As liquid flows past the vent 13, some liquid may pass through the vent 13. In order to deflect this liquid back into the drain line, a retainer 14 may be attached to the exterior of the pipe 10 over the vent 13. The retainer 14 may also be integral with the pipe 10, and may be made by casting the retainer 14 together with the pipe 10 from the same mold. In the preferred embodiment, the retainer 14 is a single piece of semi-cylindrical metal with a rounded bottom that extends vertically a short distance up the pipe 10 and is permanently attached on the sides and bottom to the surface of the pipe 10. An open end 15 allows air from the vent 13 to escape. The retainer 14 is attached at the bottom of the vent 13 so that liquid that accumulates in the retainer 14 flows back through the vent 13 and into the drain line. The attachment points are preferably watertight, and the retainer 14 is most preferably welded to the pipe 10. In alternate embodiments, the retainer 14 may be made of other suitable plumbing materials, and may be permanently or removably attached to the pipe 10. For example, the retainer 14 and pipe 10 may be PVC, and the retainer 14 may be adhered to the pipe 10 using a waterproof adhesive. Any shape or size of retainer 14 may be used as long as it allows air to escape through the vent 13 and is positioned to deflect liquid back into the drain line. Alternate embodiments may have overflow-preventive elements such as those shown in FIGS. 4 and 5 and discussed below.

FIG. 3 illustrates a typical sink installation with the preferred vented tailpiece positioned below the sink 20 drain 21 and attached to the p-trap 23. When the parts of the sink installation are functioning normally, the vent 13 allows rapid release of air in the drain line, so that liquid in the sink falls through the catch 22, the drain 21, into the vented tailpiece and quickly through the p-trap 23, with very little liquid passing through the vent 13. What little liquid does pass through is deflected by the retainer 14. However, if there is a problem in the drain line, such as inadequate venting of gas after the p-trap 23 or a clog in the drain line, the pipe 10 may fill with water and spill continuously through the vent 13 into the retainer 14. The preferred embodiment of the vented tailpiece is the simplest and most efficient embodiment, because it is an integral unit that does not have moving parts or require special positioning. Therefore, it may be used substantially universally for sinks that would benefit from it. However, it does not provide significant protection against this kind of overflow condition.

FIGS. 4-6 illustrate alternative embodiments that provide overflow protection. Referring to FIG. 4, an extension tube 40 may be permanently or removably attached to the retainer 14 at the open end 15. The extension tube 40 may be rigid or flexible. Permanent attachment may be accomplished with an adhesive, welding, solder, or similar means, depending on the material used for the retainer 14 and extension tube 40. Removable attachment may be accomplished with a clip, mating mechanism, or friction fit of the extension tube 40 into the open end 15. In the illustrated embodiment, the extension tube 40 is preferably made of a flexible, waterproof material, such as a plumbing tube or a clear or opaque rubber tube, and is long enough to extend above the fill line of the sink 20. The extension tube 40 is held substantially vertically at or near the outer surface of the sink 20. During a drain line backup, the retainer 14 and extension tube 40 fill with liquid until a hydrostatic equilibrium is reached at the vent 13, preventing further liquid from passing into the retainer 14.

Referring to FIGS. 5 and 6, an overflow valve 50 may be attached to the retainer 14 at the open end 15. In this embodiment, the retainer 14 may comprise a tube having a vertical portion 16 that is substantially parallel to the pipe 10 and an angled portion 17 that connects to the pipe 10, surrounding the vent 13. The tube may be the same material as the pipe 10, or may be a different material suitable for plumbing fixtures. In this embodiment, the retainer 14 is preferably copper. The retainer 14 may be permanently attached, such as by welding, or removably attached. In one example of removable attachment, illustrated in FIGS. 5 and 6, a threaded bulkhead 51 is attached to the pipe 10 and surrounds the vent 13, and the retainer 14 has a mated threaded portion 18 for attaching the retainer 14 to the bulkhead 51. The angled portion 17 is angled so that liquid that enters the retainer 14 flows back into the drain line through the vent 13. The angle of the angled portion 17, with respect to the pipe 10, is preferably 45 degrees.

The overflow valve 50 fits over the open end 15 of the retainer 14. The overflow valve 50 is a housing 52 attached to the retainer 14 and having one or more vent holes 53 that allow air to escape. The housing 52 may be metal, such as brass, stainless steel, or copper, or may be plastic, such as ABS or PVC. The housing 52 may be permanently or removably attached to the retainer 14 by welding, solder, adhesive, mated mechanism, or friction fit, depending on the materials used. Preferably, the housing 52 is metal like the retainer 14 and is welded to the retainer 14. The housing 52 is preferably cylindrical with a diameter of about 0.75 inches, with four vent holes 53 having a diameter of 0.125 inches, and the retainer 14 is a 0.5 inch diameter pipe.

A float 54 is disposed in the interior 55 of the housing 52, and is disposed about a pole 56 passing through or attached to the top of the housing 52. The pole 56 is a substantially rigid rod, made of metal or rubber, that suspends the float 54 above the open end 15 of the retainer 14. The float 54 is preferably an annular disc disposed around the pole 56 at the base of the pole 56. The float 54 is smaller in diameter than the housing 52, and is made of a buoyant material such as plastic, cork, or rubber. An additional rubber or cork gasket 57 may be attached to the top of the float 54 if the float 54 is made of a material, such as inexpensive Kydex® plastic, that does not completely seal the vent holes 53 on its own. Preferably, the float 54 is permanently attached to the pole 56, which passes through a hole in the top of the housing 52 that is slightly larger in diameter than the pole 56. See FIG. 6. As liquid rises through the retainer 14 into the housing 52, the float 54 rises on the surface of the liquid, pushing the pole 56 through the hole in the housing 52, until the float 54 reaches the top of the housing 52 and covers the vent holes 53, sealing the overflow valve 50. Once the drain line backup is repaired, the liquid drains back into the drain line through the vent 13, dropping the float 54 and allowing air to escape normally. In an alternative embodiment, the pole 56 is permanently attached to the top of the housing 52 and the float 54 has a hole that is slightly larger than the diameter of the pole 56, allowing it to slide along the pole 56 as the water level rises.

While there has been illustrated and described what is at present considered to be the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the invention. Therefore, it is intended that this invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. 

1. A tailpiece for installation in a sink drain line between a sink drain and a drainline trap, the tailpiece comprising: a) a pipe having a top end positioned to receive liquid flowing through the sink drain and a bottom end that attaches to the drainline trap; and b) a vent in the pipe between the top end and the bottom end.
 2. The tailpiece of claim 1 further comprising a retainer attached to the pipe over the vent such that the retainer deflects liquid passing out of the vent back into the pipe through the vent.
 3. The tailpiece of claim 2 wherein the retainer comprises an open end for releasing air that escapes through the vent.
 4. The tailpiece of claim 3 wherein the retainer is permanently attached to the pipe.
 5. The tailpiece of claim 4 wherein the pipe and retainer are metal, and wherein the retainer is welded to the pipe.
 6. The tailpiece of claim 4 wherein the pipe and retainer are plastic, and wherein the retainer is adhered to the pipe with a waterproof adhesive.
 7. The tailpiece of claim 4 wherein the retainer is integral with the pipe.
 8. The tailpiece of claim 3 wherein the retainer is semi-cylindrical.
 9. The tailpiece of claim 8 wherein the retainer has a rounded bottom that is attached to the pipe at the bottom of the vent.
 10. The tailpiece of claim 3 further comprising an extension tube attached to the retainer at the open end.
 11. The tailpiece of claim 10 wherein the extension tube is flexible.
 12. The tailpiece of claim 10 wherein the extension tube extends above the fill line of the sink.
 13. The tailpiece of claim 3 further comprising an overflow valve attached to the retainer at its open end.
 14. The tailpiece of claim 13 wherein the overflow valve comprises: a) a housing attached to the retainer; b) one or more vent holes in the housing that allow air to escape; and c) a float positioned inside the housing that floats on the surface of liquid in the housing and covers the vent holes if the housing fills with liquid.
 15. The tailpiece of claim 13 wherein the retainer comprises an angled portion and a vertical portion attached to the angled portion, the overflow valve being attached to the vertical portion.
 16. The tailpiece of claim 15 wherein the retainer is a tube.
 17. The tailpiece of claim 16 wherein the angled portion is permanently attached to the pipe, surrounding the vent.
 18. The tailpiece of claim 16 wherein the retainer is removably attached to the pipe.
 19. The tailpiece of claim 18 wherein: a) the pipe further comprises a threaded bulkhead that surrounds the vent; and b) the retainer further comprises a threaded portion attached to the angled portion, the threaded portion having threads that are mated to the threads on the bulkhead.
 20. A tailpiece for installation in a sink drain line between a sink drain and a drainline trap, the tailpiece comprising: a) a metal pipe having a top end positioned to receive liquid flowing through the sink drain and a bottom end that attaches to the drainline trap; b) a substantially circular vent in the pipe between the top end and the bottom end; and c) a semi-cylindrical metal retainer welded to the pipe over the vent, such that the retainer deflects liquid passing out of the pipe through the vent back into the pipe, the metal retainer having a rounded bottom attached to the pipe at the bottom of the vent. 